/*-------------------------------------------------------------------------
 *
 * vacuumlo.c
 *	  This removes orphaned large objects from a database.
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  contrib/vacuumlo/vacuumlo.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif

#include "libpq-fe.h"

#define atooid(x) ((Oid)strtoul((x), NULL, 10))

#define BUFSIZE 1024

extern char* optarg;
extern int optind, opterr;

enum trivalue { TRI_DEFAULT, TRI_NO, TRI_YES };

struct _param {
    char* pg_user;
    enum trivalue pg_prompt;
    char* pg_port;
    char* pg_host;
    int verbose;
    int dry_run;
    long transaction_limit;
};

static int vacuumlo(const char* database, const struct _param* param);
static void usage(const char* progname);

/*
 * This vacuums LOs of one database. It returns 0 on success, -1 on failure.
 */
static int vacuumlo(const char* database, const struct _param* param)
{
    PGconn* conn = NULL;
    PGresult *res, *res2;
    char buf[BUFSIZE];
    long matched;
    long deleted;
    int i;
    static char* password = NULL;
    bool new_pass = false;
    bool success = true;

    /* Note: password can be carried over from a previous call */
    if (param->pg_prompt == TRI_YES && password == NULL)
        password = simple_prompt("Password: ", 100, false);

    /*
     * Start the connection.  Loop until we have a password if requested by
     * backend.
     */
    do {
        new_pass = false;

        conn = PQsetdbLogin(param->pg_host, param->pg_port, NULL, NULL, database, param->pg_user, password);
        if (!conn) {
            fprintf(stderr, "Connection to database \"%s\" failed\n", database);
            return -1;
        }

        if (PQstatus(conn) == CONNECTION_BAD && PQconnectionNeedsPassword(conn) && password == NULL &&
            param->pg_prompt != TRI_NO) {
            PQfinish(conn);
            password = simple_prompt("Password: ", 100, false);
            new_pass = true;
        }
    } while (new_pass);

    /* check to see that the backend connection was successfully made */
    if (PQstatus(conn) == CONNECTION_BAD) {
        fprintf(stderr, "Connection to database \"%s\" failed:\n%s", database, PQerrorMessage(conn));
        PQfinish(conn);
        return -1;
    }

    if (param->verbose) {
        fprintf(stdout, "Connected to database \"%s\"\n", database);
        if (param->dry_run)
            fprintf(stdout, "Test run: no large objects will be removed!\n");
    }

    /*
     * Don't get fooled by any non-system catalogs
     */
    res = PQexec(conn, "SET search_path = pg_catalog");
    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
        fprintf(stderr, "Failed to set search_path:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }
    PQclear(res);

    /*
     * First we create and populate the LO temp table
     */
    buf[0] = '\0';
    strcat(buf, "CREATE TEMP TABLE vacuum_l AS ");
    if (PQserverVersion(conn) >= 90000)
        strcat(buf, "SELECT oid AS lo FROM pg_largeobject_metadata");
    else
        strcat(buf, "SELECT DISTINCT loid AS lo FROM pg_largeobject");
    res = PQexec(conn, buf);
    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
        fprintf(stderr, "Failed to create temp table:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }
    PQclear(res);

    /*
     * Analyze the temp table so that planner will generate decent plans for
     * the DELETEs below.
     */
    buf[0] = '\0';
    strcat(buf, "ANALYZE vacuum_l");
    res = PQexec(conn, buf);
    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
        fprintf(stderr, "Failed to vacuum temp table:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }
    PQclear(res);

    /*
     * Now find any candidate tables that have columns of type oid.
     *
     * NOTE: we ignore system tables and temp tables by the expedient of
     * rejecting tables in schemas named 'pg_*'.  In particular, the temp
     * table formed above is ignored, and pg_largeobject will be too. If
     * either of these were scanned, obviously we'd end up with nothing to
     * delete...
     *
     * NOTE: the system oid column is ignored, as it has attnum < 1. This
     * shouldn't matter for correctness, but it saves time.
     */
    buf[0] = '\0';
    strcat(buf, "SELECT s.nspname, c.relname, a.attname ");
    strcat(buf, "FROM pg_class c, pg_attribute a, pg_namespace s, pg_type t ");
    strcat(buf, "WHERE a.attnum > 0 AND NOT a.attisdropped ");
    strcat(buf, "      AND a.attrelid = c.oid ");
    strcat(buf, "      AND a.atttypid = t.oid ");
    strcat(buf, "      AND c.relnamespace = s.oid ");
    strcat(buf, "      AND t.typname in ('oid', 'lo') ");
    strcat(buf, "      AND c.relkind = 'r'");
    strcat(buf, "      AND s.nspname !~ '^pg_'");
    res = PQexec(conn, buf);
    if (PQresultStatus(res) != PGRES_TUPLES_OK) {
        fprintf(stderr, "Failed to find OID columns:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }

    for (i = 0; i < PQntuples(res); i++) {
        char *schema, *table, *field;

        schema = PQgetvalue(res, i, 0);
        table = PQgetvalue(res, i, 1);
        field = PQgetvalue(res, i, 2);

        if (param->verbose)
            fprintf(stdout, "Checking %s in %s.%s\n", field, schema, table);

        schema = PQescapeIdentifier(conn, schema, strlen(schema));
        table = PQescapeIdentifier(conn, table, strlen(table));
        field = PQescapeIdentifier(conn, field, strlen(field));

        if (!schema || !table || !field) {
            fprintf(stderr, "Out of memory\n");
            PQclear(res);
            PQfinish(conn);
            return -1;
        }

        snprintf(buf,
            BUFSIZE,
            "DELETE FROM vacuum_l "
            "WHERE lo IN (SELECT %s FROM %s.%s)",
            field,
            schema,
            table);
        res2 = PQexec(conn, buf);
        if (PQresultStatus(res2) != PGRES_COMMAND_OK) {
            fprintf(stderr, "Failed to check %s in table %s.%s:\n", field, schema, table);
            fprintf(stderr, "%s", PQerrorMessage(conn));
            PQclear(res2);
            PQclear(res);
            PQfinish(conn);
            return -1;
        }
        PQclear(res2);

        PQfreemem(schema);
        PQfreemem(table);
        PQfreemem(field);
    }
    PQclear(res);

    /*
     * Now, those entries remaining in vacuum_l are orphans.  Delete 'em.
     *
     * We don't want to run each delete as an individual transaction, because
     * the commit overhead would be high.  However, since 9.0 the backend will
     * acquire a lock per deleted LO, so deleting too many LOs per transaction
     * risks running out of room in the shared-memory lock table. Accordingly,
     * we delete up to transaction_limit LOs per transaction.
     */
    res = PQexec(conn, "START TRANSACTION");
    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
        fprintf(stderr, "Failed to start transaction:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }
    PQclear(res);

    buf[0] = '\0';
    strcat(buf, "SELECT lo FROM vacuum_l");
    res = PQexec(conn, buf);
    if (PQresultStatus(res) != PGRES_TUPLES_OK) {
        fprintf(stderr, "Failed to read temp table:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }

    matched = PQntuples(res);
    deleted = 0;
    for (i = 0; i < matched; i++) {
        Oid lo = atooid(PQgetvalue(res, i, 0));

        if (param->verbose) {
            fprintf(stdout, "\rRemoving lo %6u   ", lo);
            fflush(stdout);
        }

        if (param->dry_run == 0) {
            if (lo_unlink(conn, lo) < 0) {
                fprintf(stderr, "\nFailed to remove lo %u: ", lo);
                fprintf(stderr, "%s", PQerrorMessage(conn));
                if (PQtransactionStatus(conn) == PQTRANS_INERROR) {
                    success = false;
                    break;
                }
            } else
                deleted++;
        } else
            deleted++;
        if (param->transaction_limit > 0 && (deleted % param->transaction_limit) == 0) {
            res2 = PQexec(conn, "commit");
            if (PQresultStatus(res2) != PGRES_COMMAND_OK) {
                fprintf(stderr, "Failed to commit transaction:\n");
                fprintf(stderr, "%s", PQerrorMessage(conn));
                PQclear(res2);
                PQclear(res);
                PQfinish(conn);
                return -1;
            }
            PQclear(res2);
            res2 = PQexec(conn, "START TRANSACTION");
            if (PQresultStatus(res2) != PGRES_COMMAND_OK) {
                fprintf(stderr, "Failed to start transaction:\n");
                fprintf(stderr, "%s", PQerrorMessage(conn));
                PQclear(res2);
                PQclear(res);
                PQfinish(conn);
                return -1;
            }
            PQclear(res2);
        }
    }
    PQclear(res);

    /*
     * That's all folks!
     */
    res = PQexec(conn, "commit");
    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
        fprintf(stderr, "Failed to commit transaction:\n");
        fprintf(stderr, "%s", PQerrorMessage(conn));
        PQclear(res);
        PQfinish(conn);
        return -1;
    }
    PQclear(res);

    PQfinish(conn);

    if (param->verbose) {
        if (param->dry_run)
            fprintf(stdout, "\rWould remove %ld large objects from database \"%s\".\n", deleted, database);
        else if (success)
            fprintf(stdout, "\rSuccessfully removed %ld large objects from database \"%s\".\n", deleted, database);
        else
            fprintf(
                stdout, "\rRemoval from database \"%s\" failed at object %ld of %ld.\n", database, deleted, matched);
    }

    return ((param->dry_run || success) ? 0 : -1);
}

static void usage(const char* progname)
{
    printf("%s removes unreferenced large objects from databases.\n\n", progname);
    printf("Usage:\n  %s [OPTION]... DBNAME...\n\n", progname);
    printf("Options:\n");
    printf("  -l LIMIT       commit after removing each LIMIT large objects\n");
    printf("  -n             don't remove large objects, just show what would be done\n");
    printf("  -v             write a lot of progress messages\n");
    printf("  -V, --version  output version information, then exit\n");
    printf("  -?, --help     show this help, then exit\n");
    printf("\nConnection options:\n");
    printf("  -h HOSTNAME    database server host or socket directory\n");
    printf("  -p PORT        database server port\n");
    printf("  -U USERNAME    user name to connect as\n");
    printf("  -w             never prompt for password\n");
    printf("  -W             force password prompt\n");
#if ((defined(ENABLE_MULTIPLE_NODES)) || (defined(ENABLE_PRIVATEGAUSS)))
    printf("\nReport bugs to GaussDB support.\n");
#else
    printf("\nReport bugs to community@opengauss.org> or join opengauss community <https://opengauss.org>.\n");
#endif
}

int main(int argc, char** argv)
{
    int rc = 0;
    struct _param param;
    int c;
    int port;
    const char* progname = NULL;

    progname = get_progname(argv[0]);

    /* Set default parameter values */
    param.pg_user = NULL;
    param.pg_prompt = TRI_DEFAULT;
    param.pg_host = NULL;
    param.pg_port = NULL;
    param.verbose = 0;
    param.dry_run = 0;
    param.transaction_limit = 1000;

    /* Process command-line arguments */
    if (argc > 1) {
        if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0) {
            usage(progname);
            exit(0);
        }
        if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0) {
            puts("vacuumlo (PostgreSQL) " PG_VERSION);
            exit(0);
        }
    }

    while (1) {
        c = getopt(argc, argv, "h:l:U:p:vnwW");
        if (c == -1)
            break;

        switch (c) {
            case '?':
                fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
                exit(1);
            case ':':
                exit(1);
            case 'v':
                param.verbose = 1;
                break;
            case 'n':
                param.dry_run = 1;
                param.verbose = 1;
                break;
            case 'l':
                param.transaction_limit = strtol(optarg, NULL, 10);
                if (param.transaction_limit < 0) {
                    fprintf(stderr, "%s: transaction limit must not be negative (0 disables)\n", progname);
                    exit(1);
                }
                break;
            case 'U':
                param.pg_user = strdup(optarg);
                break;
            case 'w':
                param.pg_prompt = TRI_NO;
                break;
            case 'W':
                param.pg_prompt = TRI_YES;
                break;
            case 'p':
                port = strtol(optarg, NULL, 10);
                if ((port < 1) || (port > 65535)) {
                    fprintf(stderr, "%s: invalid port number: %s\n", progname, optarg);
                    exit(1);
                }
                param.pg_port = strdup(optarg);
                break;
            case 'h':
                param.pg_host = strdup(optarg);
                break;
        }
    }

    /* No database given? Show usage */
    if (optind >= argc) {
        fprintf(stderr, "vacuumlo: missing required argument: database name\n");
        fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
        exit(1);
    }

    for (c = optind; c < argc; c++) {
        /* Work on selected database */
        rc += (vacuumlo(argv[c], &param) != 0);
    }

    return rc;
}
